Control of histone methylation during differentiation

分化需要细胞整合外部信号线索与内部细胞类型信息 来执行复杂的转录程序这个过程中的错误可能会导致发展 缺陷和癌症。翻译后组蛋白修饰在协调 转录的所有阶段。虽然关于组蛋白修饰是如何发生的已经知道很多， 保持和解释，在我们的理解中存在着一个显着的差距，酶如何 催化这些修饰的复合物受到控制。该项目的长期目标是 剖析调节组蛋白修饰复合物的分子机制， 分化本提案的具体目标是调查完整性的变化， 减数分裂期间组蛋白H3 Lys 4甲基转移酶COMPASS复合物的稳定性和活性 芽殖酵母S.啤酒。我们的核心假设是有两个- 导致减数分裂特异性COMPASS失活的步骤机制， 有效的减数分裂进入和完成。第一步涉及特定于locus的Set 1中的更改 当细胞进入减数分裂时，甲基转移酶募集，而第二步涉及减数分裂- 特定的Set 1降级，以允许进展超过承诺点。两个具体目标是 来检验这个假设。目的1将定义基因座特异性Set 1拮抗作用， 减数分裂进入和执行。我们的初步和已发表的数据表明，Cdk 8激酶 RNA pol II介体复合物的模块抑制位点特异性Set 1募集。使用 分子，生物化学和遗传学方法，我们将确定是否Cdk 8依赖Set 1 拮抗作用通过直接或间接机制发生。ChIP测序将确定 随着细胞进入减数分裂程序，全基因组Cdk 8依赖性Set 1占据发生改变。目的 2将决定如何将Set 1降解纳入减数分裂程序。化学和 遗传学方法将破译减数分裂基因表达的要求， 与Set 1降解有关的减数分裂标志。利用遗传和分子方法，我们将 确定稳定Set 1对减数分裂进程和完成的影响， 监控COMPASS完整性和H3 Lys 4 ME模式。成功实现这些目标 将产生重大影响，因为它们将提供COMPASS如何 在分化过程中进行了重组。这个项目的优势在于它融合了经典的技术， 酵母遗传学、生物化学和分子生物学与当代基因组学方法 和计算。

Differentiation requires cells to integrate external signaling cues with internal cell-type information to execute complex transcriptional programs. Mistakes in this process can lead to developmental defects and cancers. Post-translational histone modifications play central roles in orchestrating all phases of transcription. While much is known regarding how histone modifications are maintained and interpreted, a significant gap exists in our understanding of how the enzyme complexes that catalyze these modifications are controlled. The long-term goal of this project is to dissect the molecular mechanisms that regulate histone modification complexes during differentiation. The specific objective of this proposal is to investigate changes in the integrity, stability, and activity of the histone H3Lys4 methyltransferase COMPASS complex during meiotic differentiation in the budding yeast S. cerevisiae. Our central hypothesis is that there is a two- step mechanism that results in meiosis-specific COMPASS inactivation that is necessary for efficient meiotic entry and completion. The first step implicates changes in locus-specific Set1 methyltransferase recruitment as cells enter meiosis, while the second step involves meiosis- specific Set1 degradation to allow progression past the commitment point. Two Specific Aims are proposed to test this hypothesis. Aim 1 will define the role of locus-specific Set1 antagonism for meiotic entry and execution. Our preliminary and published data indicate that the Cdk8 kinase module of the RNA pol II mediator complex inhibits locus-specific Set1 recruitment. Using molecular, biochemical, and genetic approaches, we will determine if Cdk8-dependent Set1 antagonism occurs via direct or indirect mechanisms. ChIP-sequencing will determine how genome-wide Cdk8-dependent Set1 occupancy is altered as cells enter the meiotic program. Aim 2 will determine how Set1 degradation is incorporated into the meiotic program. Chemical and genetic approaches will decipher the requirement of meiotic gene expression and identify the meiotic hallmarks linked to Set1 degradation. Using genetic and molecular approaches, we will determine the consequences of stabilizing Set1 on meiotic progression and completion while monitoring COMPASS integrity and H3Lys4 me patterns. Successful completion of these Aims will have a significant impact as they will provide mechanistic detail into how COMPASS is retooled during differentiation. The strength of this project is that it merges classical techniques in yeast genetics, biochemistry, and molecular biology with contemporary approaches in genomics and computation.